This invention relates to solar energy collectors and more particularly to a solar energy collector that can be operated in an air heating mode and/or liquid heating mode and is ideally suited for grain drying purposes when operated in the air heating mode.
The drying of farm crops, particularly corn requires a significant amount of energy. Generally, liquid propane or electric power is used for grain drying. Due to the large amount of energy required for grain drying, solar energy appears to be a very natural source of heat for grain drying. However, the apparent economic advantage that one should derive from the use of solar energy has not fully materialized with prior solar collectors due primarily to the fact that the solar collectors are used for a short period of time, the crop drying season, and then remain idle for the balance of the year.
This invention provides a solar energy collector then can be used during the crop drying season to dry crops and that can be used during the balance of the year for other heating purposes. In addition, the solar collector of this invention is so designed that there is minimum resistance to the air flow through the collector. Grain drying requires large volumes of air flow, up to 60,000 cubic feet per minute, heated through a moderate temperature rise of 3 to 20 Fahrenheit degrees. Fans in the 5 to 60 HP range are required to move the drying air through the grain. Any impediment to the air flow will require higher fan horsepower to move the same amount of air. The prior art solar collectors generally impede the air flow and thereby increase the required fan horsepower. The solar collector of this invention presents a minimum amount of resistance to air flow.